Deffuant Model (2000)
Agents: x_i ∈ [0,1]
At each step:
1. Pick random pair (i,j)
2. If |x_i − x_j| ≤ ε:
x_i' = x_i + μ(x_j − x_i)
x_j' = x_j + μ(x_i − x_j)
Phase transition:
ε > 0.5 → consensus (1 cluster)
ε < 0.5 → polarization
# clusters ≈ 1/(2ε) (Deffuant 2002)
Related: Hegselmann-Krause,
Axelrod culture model, CODA